Powered lawn mowers are well known. Such mowers usually comprise a deck or housing that contains a vegetation cutting element. This element may either be a rigid steel blade, a flexible mono-filament line, or some other type of cutting means. The cutting element is powered by any suitable prime mover. This element usually rotates in a cutting plane to sever the grass particles at a pre-determined height above the ground. When the position of the cutting element is vertically fixed relative to the housing, the height of cut is dependent upon the height of the housing above the ground.
Lawn mowers of this type usually include a plurality of wheels for rollably supporting the housing for movement over the ground surface. These wheels are sometimes self-propelled to assist the operator in propelling the lawn mower over the ground. The wheels are usually vertically adjustable in height relative to the housing to allow different elevations of the housing above the ground. This changes the height of cut and is desirable since different heights of cut may be required by different grass and/or weather conditions. For example, in extremely hot weather, one wishes to leave the grass longer than one would if the weather were somewhat cooler to avoid burning the grass out. This would be impossible if the mower did not have different heights of cut available.
In many lawn mowers of this type, each of the wheels is individually adjustable, Many times the wheel is rotatably supported on the housing by an eccentric link member. This link member can be rotated between different positions to effect a change in the height of the wheel relative to the housing. A locking mechanism is provided for each link member to hold the link member in any adjusted position. Since each wheel must be individually adjusted to change the height of cut, it is burdensome and somewhat time-consuming to effect such a change.
Certain lawn mowers have been known which effect the change in wheel height on all the wheels simultaneously. In such mowers, the eccentric link members for the rear wheels are mounted on through axles or shafts. In addition, a rigid adjustment bar or shaft extends between one of the front link members and one of the rear link members. Thus, one only has to adjust or rotate one of the link members to effect rotation of all four link members since the link members are rotatably joined by the axles and adjustment bar.
While the system just noted effects the height of cut adjustment with only one adjusting movement, it has certain disadvantages. For example, the use of a rigid bar does not lend itself to housing configurations which are unusual, but instead is best used with housings having straight sides or a flat deck. In such a housing the bar can easily pass between the front and rear link members without having to bend or be distorted in shape too greatly. Accordingly, design flexibility for the deck housing is lost using a rigid adjustment bar. In addition, there is no easy way to adjust the rigid bar configuration so that a tilt or angle can be put onto the deck housing between the front and rear wheels. Such an angle has to be preset according to the points at which the rigid adjustment bar attaches to the link members. There has not been any way to easily change this angle in the devices of the prior art to the best of applicants' knowledge.